Washington: A second, deeper round of automatic US budget cuts is on its way, and it is going to hit the Pentagon hard.

Already reeling from a USD 34 billion budget blow this year due to deficit-driven spending reductions known as sequestration, the Defence Department would feel an additional USD 20 billion punch in 2014.

All told, the Pentagon`s budget for next year would be cut by about 10 percent below levels approved just six months ago.

Domestic programs are spared further automatic budget cuts, a little-known wrinkle that could give Democrats some advantage in upcoming negotiations over repealing the cuts, known as sequestration or at least easing its effects.

That reality is beginning to dawn in the federal government, which allowed this year`s USD 72 billion round of cuts to take effect. Officials have a few months to try to replace an even deeper round of cuts expected to take effect in January.

The situation is a product of the fallout of a budget law enacted two years ago that set up a deficit "supercommittee" with orders to come up with USD 1.2 trillion in deficit cuts over a decade. The law included the threat of the automatic cuts as a backstop intended to force a deal.

The cuts are indeed daunting to the Pentagon, which has traditionally enjoyed sweeping bipartisan support from Congress and has seen its budget requests go mostly unchallenged during more than a decade of war in Iraq and Afghanistan.

Come January, however, the Pentagon faces a cut of USD 54 billion from current spending if Congress fails to reverse the automatic cuts, according to calculations by congressional budget aides. The base budget must be trimmed to USD 498 billion, with cuts of about 4 percent hitting already reduced spending on defence, nuclear weapons and military construction. The roughly USD 78 billion budget for overseas military operations is exempt from sequestration.

Senior military officials have repeatedly warned about the devastating effects of the automatic cuts. Yet the Pentagon also appears resigned to the possibility that it will get no relief from sequestration and that defence hawks in Congress outnumbered by Republican deficit hawks will be unable to save the military budget.

The cuts would disproportionately hit modernisation of aircraft, ships and weapons; operations and maintenance; training of the all-volunteer force; and health care. This is due in part because Obama exempted military personnel from the automatic cuts.